@pkmn/client

@pkmn/client

Package encapsulating a refactored and extended version of the generic parts of the official Pokémon Showdown's client's engine.

The package has the following goals:

• track everything Pokémon Showdown's client already tracks
• provide a single place to track all known information about a battle
• integrate seamlessly with other @pkmn projects

To that end, any divergence from the canonical Pokémon Showdown's client can be explained as desirable to meet one of more of these requirements.

Installation

$ npm install @pkmn/client

Note that either @pkmn/dex or @pkmn/sim must also be installed to provide a Dex implementation for the @pkmn/data library @pkmn/client depends on.

Usage

@pkmn/client maintains a battle's state based on information contained in the Pokémon Showdown protocol. A Battle can be instantiated with a Generations instance and used to track the state of a battle by add-ing protocol messages off the wire. The Battle can then be queried to determine information about the sides / field / Pokemon involved and their current status. The state information that can be obtained from the protocol goes beyond the information provided in the |request| messages sent from the server and together both provide a more complete view of the true state of the battle.

import {Battle} from '@pkmn/client';
import {Generations} from '@pkmn/data';
import {Dex} from '@pkmn/dex';

const battle = new Battle(new Generations(Dex));

for await (const chunk of stream) {
 // Alternatively: for (const {args, kwArgs} of Protocol.parse(chunk))
  for (const line of chunk.split('\n')) {
    battle.add(line);
  }
  battle.update(); // optional, only relevant if stream contains |request|

  ... // manipulate battle
}

The UI integration test serves as an example for how the @pkmn/client library can be used to display the results of a battle visually. Note how it makes use of multiple Handler's ordered carefully to account for when the Battle state was updated. @pkmn/view's LogFormatter is an example of a Handler which depends on being run before the client's Handler (and has been designed to work hand-in-hand with Battle).

Browser

The recommended way of using @pkmn/client in a web browser is to configure your bundler (Webpack, Rollup, Parcel, etc) to minimize it and package it with the rest of your application.

Changes

@pkmn/client departs from Pokémon Showdown's client in the following ways:

• the package builds on top of @pkmn/protocol to help improve type-safety and relies on a separate Handler which is used to build up the Battle state.
• numerous fields and their types have been renamed / rearranged / coalesced / tightened to better match the @pkmn/sim representations and the types required by other @pkmn projects.
• the package can handle |request| messages in addition to the regular output log protocol. Pokémon Showdown handles |request| messages separately and allows for the information from the request to be used to improve the accuracy of the state that has been built up from battle output with optional 'ServerPokemon' parameters to various methods, @pkmn/client merges the request state with the state it has determined from the other protocol messages to ensure the Battle state always reflects the totality of information we have received from the server.
• @pkmn/client allows for the sets of either team to be provided when a Battle is instantiated so that the set information can be included with the tracked Pokemon instances (though note that the TeamValidator inside the simulator may make modifications to the set which may cause discrepancies).

License

This package is distributed under the terms of the MIT License. Substantial amounts of the code have been derived from the portions of the Pokémon Showdown client which are distributed under the MIT License.